From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 492821C29 for ; Wed, 23 Nov 2022 09:39:00 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 973BEC433D6; Wed, 23 Nov 2022 09:38:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1669196340; bh=HQscL/X2mZZMiD2EO9LRp3Z7Z2YTMW1b4xrCZaLOm+k=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=O1T/dln7CFLXqF41IeZq8feVq1TtoXNI8FPvb66pFG3EnTyIlyHhyQcgNPC/WfD7h Y/G5g901yiBiTDnLy68BavPMAwB/pBQ0CU7/PCLPpML5tZm5gkGuhw6TN4jXKs/WTk TeDP4kLvr08O5c9FdBm45g7ph6T2BmHJQizOMZ9M= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Zhao Gongyi , "Masami Hiramatsu (Google)" , Li Huafei , Sasha Levin Subject: [PATCH 5.15 166/181] kprobes: Skip clearing aggrprobes post_handler in kprobe-on-ftrace case Date: Wed, 23 Nov 2022 09:52:09 +0100 Message-Id: <20221123084609.517856993@linuxfoundation.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221123084602.707860461@linuxfoundation.org> References: <20221123084602.707860461@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Li Huafei [ Upstream commit 5dd7caf0bdc5d0bae7cf9776b4d739fb09bd5ebb ] In __unregister_kprobe_top(), if the currently unregistered probe has post_handler but other child probes of the aggrprobe do not have post_handler, the post_handler of the aggrprobe is cleared. If this is a ftrace-based probe, there is a problem. In later calls to disarm_kprobe(), we will use kprobe_ftrace_ops because post_handler is NULL. But we're armed with kprobe_ipmodify_ops. This triggers a WARN in __disarm_kprobe_ftrace() and may even cause use-after-free: Failed to disarm kprobe-ftrace at kernel_clone+0x0/0x3c0 (error -2) WARNING: CPU: 5 PID: 137 at kernel/kprobes.c:1135 __disarm_kprobe_ftrace.isra.21+0xcf/0xe0 Modules linked in: testKprobe_007(-) CPU: 5 PID: 137 Comm: rmmod Not tainted 6.1.0-rc4-dirty #18 [...] Call Trace: __disable_kprobe+0xcd/0xe0 __unregister_kprobe_top+0x12/0x150 ? mutex_lock+0xe/0x30 unregister_kprobes.part.23+0x31/0xa0 unregister_kprobe+0x32/0x40 __x64_sys_delete_module+0x15e/0x260 ? do_user_addr_fault+0x2cd/0x6b0 do_syscall_64+0x3a/0x90 entry_SYSCALL_64_after_hwframe+0x63/0xcd [...] For the kprobe-on-ftrace case, we keep the post_handler setting to identify this aggrprobe armed with kprobe_ipmodify_ops. This way we can disarm it correctly. Link: https://lore.kernel.org/all/20221112070000.35299-1-lihuafei1@huawei.com/ Fixes: 0bc11ed5ab60 ("kprobes: Allow kprobes coexist with livepatch") Reported-by: Zhao Gongyi Suggested-by: Masami Hiramatsu (Google) Signed-off-by: Li Huafei Acked-by: Masami Hiramatsu (Google) Signed-off-by: Masami Hiramatsu (Google) Signed-off-by: Sasha Levin --- kernel/kprobes.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 55fffb7e6f1c..23af2f8e8563 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -1760,7 +1760,13 @@ static int __unregister_kprobe_top(struct kprobe *p) if ((list_p != p) && (list_p->post_handler)) goto noclean; } - ap->post_handler = NULL; + /* + * For the kprobe-on-ftrace case, we keep the + * post_handler setting to identify this aggrprobe + * armed with kprobe_ipmodify_ops. + */ + if (!kprobe_ftrace(ap)) + ap->post_handler = NULL; } noclean: /* -- 2.35.1